Concept: Systemic inflammatory response syndrome

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Local and systemic inflammatory responses are initiated early after traumatic brain injury (TBI), and may play a key role in the secondary injury processes resulting in neuronal loss and neurological deficits. However, the mechanisms responsible for the rapid expansion of neuroinflammation and its long-term progression have yet to be elucidated. Here, we investigate the role of microparticles (MP), a member of the extracellular vesicle family, in the exchange of pro-inflammatory molecules between brain immune cells, as well as their transfer to the systemic circulation, as key pathways of inflammation propagation following brain trauma.

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Prior to 2001 there was no standard for early management of severe sepsis and septic shock in the emergency department. In the presence of standard or usual care, the prevailing mortality was over 40-50 %. In response, a systems-based approach, similar to that in acute myocardial infarction, stroke and trauma, called early goal-directed therapy was compared to standard care and this clinical trial resulted in a significant mortality reduction. Since the publication of that trial, similar outcome benefits have been reported in over 70 observational and randomized controlled studies comprising over 70,000 patients. As a result, early goal-directed therapy was largely incorporated into the first 6 hours of sepsis management (resuscitation bundle) adopted by the Surviving Sepsis Campaign and disseminated internationally as the standard of care for early sepsis management. Recently a trio of trials (ProCESS, ARISE, and ProMISe), while reporting an all-time low sepsis mortality, question the continued need for all of the elements of early goal-directed therapy or the need for protocolized care for patients with severe and septic shock. A review of the early hemodynamic pathogenesis, historical development, and definition of early goal-directed therapy, comparing trial conduction methodology and the changing landscape of sepsis mortality, are essential for an appropriate interpretation of these trials and their conclusions.

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The epidemiology of the systemic inflammatory response syndrome (SIRS) in children is poorly understood. We sought to determine national estimates of the incidence of pediatric SIRS and its corresponding clinical etiologies presenting to US emergency departments (EDs) using current definitions.

The role of mitochondrial dysfunction has not been thoroughly clarified in the pathogenesis of critically ill patients. The objective of this study was to investigate mitochondrial membrane potential (ΔΨm) and apoptosis in circulating platelets in patients with systemic inflammatory response syndrome (SIRS).

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After numerous negative randomized trials testing drugs for severe sepsis and/or septic shock, the blood purification approach remains one possibility. Many techniques have been proposed, having in common the goal to eliminate blood and/or plasma factors, supposed to play a negative role in outcomes. Among these, high dose of hemofiltration, high volume hemofiltration, high permeability hemofiltration and specific or non-specific hemoperfusion or hemoadsorption have been proposed. Until now, a poor level of proof has been published, questioning the pertinence of such a strategy. To have a chance to succeed, immune monitoring has to be performed to select suitable patients regarding their immune status, the intensity of inflammation and their cellular function. Because of the potential interaction with mediators and cell capture, Rimmelé and colleagues published the results obtained with an in vitro set up, testing different adsorption cartridges in comparison to hemofiltration. They nicely confirmed the complex impact on mediator levels and cell capture and phenotype. This is certainly a more systematic approach to better understand the action of such adsorbing cartridges, which has to be developed.

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Aggressive dual antiplatelet therapy is associated not only with more bleeding, impaired wound healing, and potentially more solid cancer rates but it also causes higher infection risks including sepsis, and systemic inflammatory response syndrome (SIRS). This may be especially true considering the alarming off-label use of prasugrel. A 65-year-old white male patient with a history of myocardial infarction treated with percutaneous coronary intervention and implantation of 2 bare metal stents, was treated with off-label clopidogrel for 4 years, including a double daily dose (150 mg) for the initial 13 months. Still on clopidogrel, the patient was hospitalized with suspected pneumonia. A diagnostic cardiac catheterization revealed a 60%-70% blockage of the mid left anterior descending, but there was no need for coronary intervention. At discharge, clopidogrel 75 mg/d was switched over to off-label prasugrel 10 mg/d on top of aspirin (81 mg/d). On day 3 after prasugrel was given, a football-sized bruise appeared on the patient’s lower right abdomen, but computed tomography results were unremarkable. On day 6 after administration of prasugrel, the patient became dizzy, disoriented, confused, experienced difficulty breathing, severe headache, weakness, intensive petechial rash covering the entire body, and breathing difficulty requiring ventilation. Within 24 hours, the patient was unable to correctly identify his age; his eyes were pale in color to almost colorless and when hearing a sound he would turn his entire head toward the sound and he appeared to be blind. His lungs, liver, and kidneys began to show signs of failure over the next 5-9 days. Sixteen days after the administration of the first prasugrel dose, the patient died of sepsis complicated with SIRS. Aggressive off-label use of clopidogrel (double dose for 13 months, and >4 years overall duration), followed by off-label switchover to the highest daily dose (10 mg) prasugrel may trigger sepsis and fatal SIRS. The mechanism responsible for such harmful association is probably indirect, and involves the weakening of platelet-neutrophil-endothelial crosstalk necessary to combat infections, and/or keep inflammation from spreading.

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BACKGROUND:: In 1992, the first consensus definition of severe sepsis was published. Subsequent epidemiologic estimates were collected using administrative data, but ongoing discrepancies in the definition of severe sepsis produced large differences in estimates. OBJECTIVES:: We seek to describe the variations in prevalence and mortality of severe sepsis in the United States using four methods of database abstraction. We hypothesized that different methodologies of capturing cases of severe sepsis would result in disparate estimates of prevalence and mortality. DESIGN, SETTING, PARTICIPANTS:: Using a nationally representative sample, four previously published methods (Angus et al, Martin et al, Dombrovskiy et al, and Wang et al) were used to gather cases of severe sepsis over a 6-yr period (2004-2009). In addition, the use of new ICD-9 sepsis codes was compared with previous methods. MEASUREMENTS:: Annual national prevalence and in-hospital mortality of severe sepsis. RESULTS:: The average annual prevalence varied by as much as 3.5-fold depending on method used and ranged from 894,013 (300/100,000 population) to 3,110,630 (1,031/100,000) using the methods of Dombrovskiy et al and Wang et al, respectively. Average annual increase in the prevalence of severe sepsis was similar (13.0% to 13.3%) across all methods. In-hospital mortality ranged from 14.7% to 29.9% using abstraction methods of Wang et al and Dombrovskiy et al. Using all methods, there was a decrease in in-hospital mortality across the 6-yr period (35.2% to 25.6% [Dombrovskiy et al] and 17.8% to 12.1% [Wang et al]). Use of ICD-9 sepsis codes more than doubled over the 6-year period (158,722 - 489,632 [995.92 severe sepsis], 131,719 - 303,615 [785.52 septic shock]). CONCLUSION:: There is substantial variability in prevalence and mortality of severe sepsis depending on the method of database abstraction used. A uniform, consistent method is needed for use in national registries to facilitate accurate assessment of clinical interventions and outcome comparisons between hospitals and regions.

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Introduction: Over the last two decades, many of the mechanisms underlying the pathophysiology of sepsis have been uncovered, but this has not led to the development of effective therapies for sepsis. Despite improvements in the general care of critically ill patients in recent years, mortality rates for patients with severe sepsis and septic shock remain high at 30 to 50% and there is an urgent need to develop new, effective therapeutic strategies. Areas covered: Attempts to develop a therapy for sepsis have focused on modulating this immune response. Past and present clinical research in this field are reviewed and promising candidates and approaches for the future are discussed. Expert opinion: Many reasons have been put forward over the years to explain the many negative results from trials of immunomodulatory therapies. Future studies need to be designed to specifically target patients who can benefit from the intervention being studied rather than at the sepsis population in general. The timing of administration of potential therapies also needs to be taken more into consideration.

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Inflammation in the course of systemic inflammatory response syndrome (SIRS) or sepsis often results in dysregulation of the hypothalamic-pituitary-adrenal axis; however, the underlying mechanisms are not well understood. The adrenal gland is highly vascularized; thus, we hypothesized that endothelial dysfunction may actively participate in inflammation-related adrenal insufficiency. To address this hypothesis, we used the properties of developmental endothelial locus-1 (Del-1), which is an endothelial-derived anti-inflammatory factor that antagonizes integrin-dependent leukocyte adhesion. Here we identified that Del-1 is expressed in the adrenal gland and that its expression was down-regulated upon SIRS induction by systemic lipopolysaccharide administration. Furthermore, we observed increased leukocyte accumulation, inflammation, and higher apoptosis in the adrenal glands of Del-1-deficient mice as compared with wild-type mice. Strikingly, Del-1 deficiency was also associated with reduced corticosterone and ACTH levels 24 hours after lipopolysaccharide administration. Together, these data suggest that Del-1 may act as a gatekeeper of adrenal gland inflammation and may regulate the integrity of the hypothalamic-pituitary-adrenal axis stress response, thereby modulating adrenal (dys)function in the course of SIRS.